JOURNAL OF SCIENCE (KHARAZMI UNIVERSITY)
Year:2011 | Volume:10 | Issue:4|Papers Count:8

advances in our knowledge of effects of rhizospher microbipota such as soil microorganisms and nutrient elements on growth and the function of plants effects of soil texture, the physical parameters and alternative culture of plants on vesicular-arbuscular (VA) fungus and other soil microorganisms isnot fully understood. Evidence show that nodulation of P.vulgaris in soils of Dehaghan (Isfahan priviance) is very low. In the present study, effects of some of physical characteristics of soils was of 6 soil types were investigated on two varities of bean (Talash and Khomein).The experiments were carrieded a Completely Randomized Design with 4 replications. Soil samples were collected from, legumes fields which were alternatively cultural wheat-bean, barely-bean and cicer of Dehaghan during April 2005 soils of each field were lighted by adding half amount of sand. Then, soil texture, pH, EC, Amount of N in soils, number of spores of VA and presence rhizobium in soils were assessed. Seeds of two varietes of Phaseolus were growth in a pot culture experimental in different soils. At two leaved stage, plants were devided into two groups. The first group was treated with 65 cc of nutrient medium minus nitrogen four times at 7 days intervals. The second group was irrigated with tap water only. After 50 days, plants were harvested and number of nodules of roots, spores of VAM in soil were counted and mycorrhizal colonization, biomass of root and shoot, amount of P,K,Zn in plants were measured. The results showed that mycorrhizal colonization, nodulation of root and other parameters in soil of wheat-bean field significantly increased. While many measured parameters decrease in soil of wheat-barely field. This soil showed decrease in nodulation and contamination fusarium fungi. The results are discussed with regard to the fact that barely excretes materials that can alter the soil environment, prevent rhizobium to be active and provide fusarium fungi to be active.

Maize (Zea mays L) plants grown in hydroponic culture were treated with 0, 50 and 100mmCdCl2. Growth parameters and some biochemical changes were studied in roots and shoots of plants. The results showed that with increasing Cd concentration, root weight, pigment contents (chlorophyll a and b and total carotenoids), reduction of dichlorophenol indophenol, nitrate content and nitrate reductase activity were decreased, while free amino acide, non-protein thiols, endogenous H2O2 and malondealdyde as indicator lipid of peroxidation were increased.

Halophilic bacteria cannot growth without NaCl and they have optimum growth in high salinity media. Halobacteria are chemoorganotroph and the most species are aerobic. Bacteriorhodopsin is a light driven proton pump that found only in halobacteria. In this study H. salinarum that isolated in previous research from saline environment in Iran were used for isolation of purple membrane. The method of Yucel et al (1995) was applied for isolation of purple membrane of H. salinarum. The stages of this method include dialysis and centrifuge at high speed. Spectrophotometery analysis at 560 nm and absorbance ratio 280.560 nm were used for conform the purity of purple membrane. The activity of purple membrane was assayed as change of pH in salt solution contains MgCl2 and KCl. By using of microwave radiation apparatus the ability of microwave absorbance were measured. The result of isolation of purple membrane indicated that the 280.560 absorbance ratio in this spectrum was 3.3 that confirm the purity of purple membrane. Extracted purple membrane from 4 liter of culture media was 35 milligram. This extracted PM could decrease of pH (0.15 units per 6 hours) and absorb 60 % of microwave radiation. In conclusion there is very diversity between halophilic archaea in Iran ecosystem and extracted PM is favorable for nanotechnology application.

The effects of cadmium and iron interaction on some physiological parameters in rice (Oryza sativa L.cv.fajr) plant were studied. The four days old seedlings were transferred to pots containing sand, irrigated with Hoagland solution in growth chamber. The 15 days old plants were treated with 0, 50 and 100 mM CdCl2 supplemented with 5, 10 and 20 ppm Fe as Fe-EDTA. Plants were grown under controlled condition and harvested after 30 days for measurements of some biochemical and physiological parameters. Treatments were conducted with four replications. Under Cd stress, growth of plant decreased. In plants treated with CdCl2, relative growth rate, net assimilation rate and photosynthetic rate were decreased. Addition of Fe-EDTA (10 and 20 ppm) moderated cadmium effects. Under Cd stress without Fe, respiration rate and CO2 compenstation point increased, however, in solutions containing CdCl2 and Fe-EDTA, respirations rate and CO2 compenstation point decreased. In plants treated with CdCl2, catalase activity increased. However, after increasing Fe in solution containing CdCl2, catalase activity decreased. Therefore, the results indicated that in CdCl2 treated plants with increasing Fe-EDTA, the toxic effects of Cd decreased.

Plant diseases especially plant viruses cause significant crop decrease. Meristem culture is the most important method for virus free plant production. The aim of this investigation was to establish an effective protocol for callus induction and plant regeneration from meristem culture of potato (Solanum tuberosum L. var.premier) tissues. Calli were induced from axillary meristems of Solanum tuberosum L. (cv. Premier) on MS medium containing 2,4-D (0, 0.5, 1, 1.5, 2 and 2.5 mg/l) and kinetin (0, 0.5, 1 and 1.5 mg/l). MS medium with 2 mg/l 2,4-D and 1.5 mg/l kinetin, was effective for callus induction. Plantlets were regenerated after 9 weeks. In terms of shoot regeneration and its growth, 1 mg/l 2,4-D and 1.5 mg/l kinetin were the most effective treatment. Maximum number of leaves were produced by plantlets growing on MS medium containing 1 mg/l 2,4-D and 1 mg/l kinetin. High frequency of root formation and its growth were observed on the same medium.

Ailanthus altissima (tree of heaven) belongs to Simaroubaceae. It is a dioecious plant and its flowers are unisexual, but there are unfertile reproductive organs of opposite sex rudimentarily. In this study, the structure of flower and pollen grain and anther development especially in staminate flowers were studied using light and scanning electron microscopes. Results showed that each staminate flower contained 10 functional stamens and 5 sterile carpels without ovule and embryo sac. Pistillate flowers produce a gynocium with 3-5 carpels (mostly 5 carpels) and 10 abortive stamens without pollen sacs and pollen grains. The anther wall in staminate flowers is composed of epidermis, endothecium, 2-3 middle layers and glandular tapetum. Tapetal layer is multinucleate and elongate. The cytokinesis following meiosis is simultaneous, producing tetrahedral and rhomb- shaped tetrads. Under SEM, pollen grains seems prolate, elliptic, isopolar and tricolporate. Exine sculpture is straite- reticulate.

Aquatic ecosystems are the main biotic ecosystems that contain variety of plant species and their destruction result in the reduction of plant species diversity. In the present investigation, species diversity of aquatic plants in permanent, seasonal, forest wetlands and ricelands of the west and east of Mazandaran province was determined. First, 30 habitats were determined on the map and the total 161 samples, based on systematic-random sampling, were established. 126 species of aquatic plant of the habitats were collected and the cover of each species, based on the area of quadrate that accupied by plants, was recorded. The results showed that species diversity of aquatic plants in the west and east is governed by the moisture gradient. Based on De Martonne classification system of climate, the west and east of Mazandaran province have wet and mediterranean climate, respectively. Therefore, the condition for the growth of aquatic plants in the west is more appropriate than in the east. Species diversity of wetlands and ricelands in the west was higher than that in the east. In this study, classification system of den Hartog & Veld for aquatic plants that classify them as hygrophytes, real aquatic and wetland species was applied and diversity indices for all three categories were calculated. The results revealed that diversity of hygrophytes is the highest among them and the real aquatic plants have higher species diversity than wetlands. T-test, based on Shannon index, showed significant differences between diversity of the west and east as well as between three group of macrophytes (P<0.05).